of terre haute



i Reiaued Dem 11, 1928.

UNITED STATES Re. l7,l57

PATENT OFFICE.

CHARLES BOGIN, OF THREE HAl'J'IE, INDIANA, ASSIGNOR T COMMERCIAL soLvlm'rs CORPORATION, or Team: HAUTE; INDIANA, A CORPORATION OF MARYLAND.

PURIFICATION OF BUTYRIC ALDEHYDE.

I;- In Drawing. Original Nb. 1,558,067, dated October 6, 1925, Serial No. 712,888, filed Kay 12, 10M.

, lpplication for reinue filed April 7, 1928. Serial No. 268,310.

M invention relates to an improved procass or the distillation and purification of lm'tyric aldehydes. The process allows a aim is and easy purification unaccompanied bytl'ie-ionnation of high hoilinf; condensation and polymerization products uring distillation, and affords a material increase in yield over that obtained b ordinary methods." It is well known tiat aliphatic aldehydcs are readily condensed or p0 ymerized by the action of heat and impurities. In the case of but ric aldehydcs, i.,c., normal butyric aide .hy e and isobntyric aldehyde, it is necessary to Iraelionally distill the crude '.lci:hydes several times to secure products of satisfactory purity and while each successive distillation gives an increasing purity of the aldchydc, the fraction itself is reduced in quantity by each distillation, owing to the formation of high-boiling n'oducts.

1 have discovered that the presence of a small amount of waterin the liquid during the distillation of a butyric aldehyde completely inhibits the formation of condensation or polymerization products and allows a more economical production oi pure aldehyde. In the presence of water the aldehyde dlstills over use constant-boiling mixture with the ,water, but this phenomenon is not a detriment to the process as most of the water separates out when the vapors are condensed.

The beneficial result accruing from the additi'on of water is not due to the formation of a constant-boiling mixture but rather to 85 the presence of water in'the liquid in the still. In practise, the water may be conveniently added to the liquid before distillation, or it may be added in small quantities during distillation. As an alternative, steam may be 40 introduced into the aldehyde at room temperature in which case the aldehyde becomes saturated with water through condensation of the vapors and the temperature is gradually raised to the proper tcmperature for distiliation.

' In any case, it is necessary that water be present in the liquid throughout the'course of distillation, for if there is not suflicient water present to form a constant-boiling-mixture with all of the aldehyde to be distilled, the water will be eliminated in the early stages of distillation. In the latter case it is Ohvious that the aldehyde in the stillwill be hence con ensation and dry durin the last stages of distillation and polymerization losses will occur.

Having gcnerallydescribed my invention I will give a specific example of its use.

Normal hutyric aldehyde as prepared bythe catal 'tic deli drogenation of normal primer huty alcoho (sec U. S. Patent 1,418,448 contains bntyl alcohol, butyl hutyrate, acetals, and various other condensation and polymerization products. In purifying this material on an industrial-scale it is necessary to l'vlllsl'lll the material several times and while each distillation vgives purer aldehyde fraction, thotota-l yield is greatly cutdown by the 'ttn-nml'ion of. condensation and polymerization products. l 1

For example, if relatively pure normalbutyrlc aldehyde boiling at 74-75C.israther rapidly distilled, the loss dueto the-formation o l-hyn-oducts amounts to about ten per cent, and it the distillation is run at a, slower rate the loss from this source may be as high as forty per cent. Distillation under a vacuum does not con'ipletely eliminate these losses. In any case, the addition of small an'iounts of water or steam as previously described eliminates theformation of condensation and polymerization products and the matorial may he redistilled as many times as is desired without loss Normal hntyric aldehyde forms a constantboiling mixture with water which distills at about 68 C. and the vapors of this mixture contain about six per cent of the latter sub stance. ()n condensation of the vapor, most of the water separates out as a separate layer, since the aldeh do will dissolve only about two per cent ot water. In accordance with my invention six alent amount of we maybe added to the liquid in small portions durin distillation; If desired, thedistillation of utyrie aide hyde in the presence of water may be condueted in iii-partial vacuum, and this type of distillation 18 particularly useful, when-for er 'cent of water is added to the aldehyde be oragistillation or an equivdistillation at a slow: rm.

buiyfi'clildehyde, or at ation is desired to obtain dry aldehyde, the water can readily be removed from the aldehyde by salting.

Now, having described my invention, I claim the following as new and novel 1. A rocess for the purification of butyric aldehyd consisting in vacuum-distilling the aldehyde in the presence of suilicient water to form a constant-boiling mixture with the aldehyde.

2. A process for the purification of normal butyric aldehyde consisting in distilling the aldehyde in thr presence of six per cent of water.

3. A process for the purification of normal butyric aldehyde consisting in distilling the aldehyde in the presence of six per cent of water, and removing the moisture from the aldehyde by salting.

4. A process for the purification of normal butyric aldeh do consisting in vacuum-distilhng the aldhhyde in the presence of sufficient water to form a constant-boiling mixture with the aldehyde.

5. In a recess for the purification of normal butyric aldehyde, the step which consists in maintaining the aldehyde in a moist condition during distillation by adding small c quantities of water as required 6. A process for the purification of relative'l pure butyric aldehyde by distillation, which consists in conducting said distillation under reduced pressure and in the presence of sutlicient Water to form a constant boiling mixture with the aldehyde whereby the formation of polymerization and condensation products of said aldehyde is in hibited.

7. A process for the purification of relatively pure normal butyric aldehyde by distillationJwhich consists in conducting, said distillati n under reduced pressure and in the patience of nifiicient water to one a constant boiling mixture with the aldehyde whereby the formation of polymerization and condensation prodiicts of said aldehyde is inhibited.

8. A rocess for the purification of butyrio aldehyte by distillation, which consists in conducting the said distillation under lednced pressure and with water present thru-,

out the distillation. wherehy the formation of polymerization and comlensation products of the sald aldehydeis lnhgbited.

9. In a process for tllGlJilI'lllCfililOIl by (115* hol, the aldehyde being present in such proportion that in the absence of Water it would react with itself on heating to form polymerization and condensation products, the

improvement which consists in conducting the distillation with water present thruout the distillation, whereby the formation .of polymerization and condensation products of saic aldehyde is inhibited.

CHARLES HOGIN.

55 tillation of a mixture'containing a major r 

